Question

One of the forms of a naturally occurring solid compound P is usually used for making the floors of houses. On adding a few drops of dilute hydrochloric acid to P, brisk effervescence is produced. When 50 g of reactant P was heated strongly, then 22 g of a gas Q and 28 g of a solid R were produced brisk effervescence on adding dilute HCl to P. Gas Q is said to cause global warming whereas solid R is used for whitewashing.

(a) What is (i) solid P (ii) gas Q, and (iii) solid R?
(b) What is the total mass of Q and R obtained from 50 g of P?
(c) How does the total mass of Q and R form compare with the mass of P taken?
(d) What conclusion do you get from the comparison of masses of products and reactant?
(e) Which law of chemical combination is illustrated by the example given in this problem?

Answer 1

(a) (i) Calcium carbonate $CaC{O}_3$ in the form of marble

(ii) Carbon dioxide $C{O}_2$

(iii) Calcium Oxide $CaO$

(b) 50 g

(c) Total mass of Q and R (50g) is equal to the mass of P taken (50g)

(d) Total mass of products is equal to the total mass of reactants.

(e) The law of conservation of mass.